Electron-beam resists conductive

Also worthy of mention is the introduction of conductive electron-beam resists that eliminate the charging effect that is so troublesome in electron-beam lithography. Todokaro et al. accomplished this by using a partially chloromethylated poly(diphenylsiloxane) as the top imaging resist in a bilayer system, and using the ionically conductive ammonium salt of poly(p-styrene sulfonate) (XXI) as the bottom layer. 

A negative deep UV resist can be produced from a composition of 3-octylPT with the cross-linker ethylene [l,2-bis(4-azido-2,3,5,6-tetrafluorobenzoate)] [150]. Grid patterns can be reproduced without distortion on an electrically conductive electron beam resist material containing substituted PT like 3-dodecyloxyPT [151,152]. 

Photoresists and electron-beam resists are the key to the success of VLSI electronic circuits. Without these resists, most electronic equipment would not exist. These polymers are spun onto the semiconductor and exposed to the circuit pattern leading to main chain scission or crosslinking. Subsequently, unpolymerised sections are removed. This process is employed either in wet or in dry conditions. This is known as the photolithographic process, which is part of the semiconductor fabrication technology. Further treatment includes diffusion of various semiconductor elements and metallisation for conduction lines. Layer by layer, the total package is developed. Current research is now directed toward finer features in the patterns and changes in the surface characteristics for subsequent layers. 

Conductive polymers have also been studied by IBM as potential electron beam resist materials for use in semiconductor processing [123]. Because they are conducting materials, there are no charging problems as are often experienced with conventional materials, and negative images... 

PT and 3-butylPT as electrically conductive materials are useful as electron beam resists [148]. A negative electron beam resist can be produced by an electron beam to form functionalization and cross-linking in 3-octylPT in a single step creating submicron scale polymer structures carrying functionalized groups [149, 150]. 

Lithographic Characterization. Electron-beam exposures were conducted on an EBES system operating at 20 kV, with a beam address and spot size both equal to 0.25 ym. Electron response parameters were evaluated using linewidth control patterns. P(SI-CMS) was spray developed after exposure using an APT Model 915 resist processor in toluene-methanol (1 1) for 30 sec followed by a methanol rinse for 45 sec. Aqueous solutions of tetramethylammonium hydroxide (TMAH, 25% in water, Fluka Inc.) were used for the novolac resist development. Exposed films were dip-developed for 20 sec. in TMAH-water (1 2.5) solutions. 

---